The importance of additive manufacturing for optical components and systems is steadily increasing. Conventional 3D printing processes such as multi-jet modeling or stereo lithography were initially used to realize passive optical components. The advantage is that with the help of additive manufacturing optical components can be realized with a complex structure. The challenge is thereby the surface quality of the components produced. Due to the process-related layer structure, steps occur on curved surfaces. Another disadvantage of the layer structure is that it acts on the one hand like a diffraction grating and on the other hand, it contributes to the volume scattering of the light. These disadvantages are attempted to be compensated by adapted printing or post-processing methods. Irrespective of this, the 3D printing of passive optical components has a wide variety of application fields, especially in the field of illumination.
The next step in the additive manufacturing of optical components is now to achieve a higher functionalization of the components, thus turning form passive to active optics, meaning that besides shaping of light rays the component can emit light on its own. Specifically, this means that the printed materials are mixed with other materials to allow additional light emission.
In this talk, the potential of additive manufacturing of passive optical components is introduced by examples. The main part of the talk then focuses on the active 3D printed optical components. For this purpose, we present two different concepts. On the one hand, the integration of optically active quantum dots (for example, CdSe / ZnS nanoparticles) in 3D printing materials. These nanoparticles emit a defined wavelength when excited by UV light. It would be desirable now that not only quantum dots of a certain size / type are printed in an optical component, but also that locally a material mix of different quantum dots can be realized. Thus, a single optical component can emit spatially resolved different wavelengths. In order to do so, we rebuilt a standard stereolithography printer so that we can use different materials in x, y plane and z direction. In this way, we realized an optically active analysis chip for biological samples.
The second concept is 3D printing of a random laser. For this purpose, we mixed nanoparticles (Nd-YAG particles) and Rhodamin as an active material into the 3Dprinting polymer. We show different forms of optically active components printed with this material. In order to prove the effect of random lasing, we pumped the samples with pulsed laser light (10Hz Nd-YAG laser, 532nm) and measured the emitted laser radiation.
Finally, we give a brief presentation of the development of an additive manufacturing platform based on robots. The aim of the platform is to enable additive manufacturing with 6 degrees of freedom. In the development of the platform, we take the requirements for printing of optical components into account.